Axle suspension of rigid axles

ABSTRACT

An axle suspension of rigid axles is presented, on the axle body ( 1 ) of which a steering triangle ( 2 ) as well as two longitudinal control arms ( 3, 4 ), which are located at spaced locations from the steering triangle and have different vertical positions, and additionally a stabilizing device ( 5 ) are arranged. The steering triangle has two control arms ( 2.1  and  2.2 ), which form an angle with one another and are fastened to a central joint ( 2.3 ), on the one hand, and are connected to the vehicle body via a guiding joint ( 2.4  and  2.5 ) each, on the other hand. The following geometric axes of coordinates are defined on the axle suspension: a first horizontal axis ( 12 ), which extends in the transverse direction of the vehicle and forms the central axis of the axle body ( 1 ) at the same time as well as a second horizontal axis ( 13 ), which extends in the center of the vehicle and in the longitudinal direction of the vehicle and intersects the axis ( 12 ) at right angles and a vertical axis ( 11 ) intersecting the intersection of the horizontal axes ( 12  and  13 ). The central joint ( 2.3 ) of the steering triangle ( 2 ) is mounted on the axle body with an offset from at least one of the axes ( 11  through  13 ).

FIELD OF THE INVENTION

The present invention pertains to an axle suspension of rigid axles formotor vehicles as they can be used predominantly in medium and heavyutility vehicles (UVs). Prior-art axle designs comprise usually asteering triangle fastened on the axle body above the rigid axle of thevehicle and a plurality: of longitudinal control arms arranged under thevehicle axle as well as additional stabilizing device. The steeringtriangle has two control arms, which form an angle with one another andare fastened to a central joint, on the one hand, and are connected viaa guiding joint to the vehicle body, on the other hand. As is known,mostly molecular joints are used as the joints.

BACKGROUND OF THE INVENTION

The housing for the differential is frequently integrated on the axlebody, approximately in the middle of the axle. The fastening of thecentral joint of the steering triangle is then additionally arranged onthis housing, so that an unusually large space must be made availablefor installation for the axle suspension. This is no longer acceptablein the manufacture of modern automobiles and especially in the case oflow-platform vehicles.

SUMMARY AND OBJECTS OF THE MENTION

The basic technical object of the present invention is to provide anaxle suspension of rigid axles which requires a smaller space forinstallation than do prior-art embodiments while the stability of thevehicle is increased and it makes it at the same time possible to reducethe tendency of the vehicle to rolling and rocking.

Furthermore, it is an object of the invention to provide an axlesuspension that is maintenance-friendly and that is able to bemanufactured and installed in a simple manner. It is still anotherobject of the invention to use standardized components where practical.

According to the invention, an axle suspension of rigid axles isprovided on an axle body. The suspension includes a steering triangle aswell as two longitudinal control arms located at spaced locations fromthe steering triangle, the two longitudinal control arms havingdifferent vertical positions. A stabilizing device is provided. The twocontrol arms form an angle with one another and are fastened to acentral joint and are each connected to the vehicle body via a guidingjoint. The geometric axes of coordinates of the axle suspension is suchthat a first horizontal axis extending in the transverse direction ofthe vehicle and forms the central axis of the axle body at the sametime. A second horizontal axis extends in the center of the vehicle andin the longitudinal direction of the vehicle and intersects the firsthorizontal axis at right angles. A vertical axis intersects theintersection of the two horizontal axes. The central joint of thesteering triangle and/or the fastening of at least one of thelongitudinal control arms are mounted on the axle body with an offset inrelation to at least one of the two horizontal axes and the verticalaxis.

The geometric axes of coordinates defined on the axle suspension providea better understanding of the relationship between features of theinvention. The first horizontal axis, which extends in the transversedirection of the vehicle and also forms the central axis of the axlebody, and the second horizontal axis, which extends in the center of thevehicle and in the longitudinal direction of the vehicle intersect at apoint M where the first horizontal axis extends at right angles to thesecond horizontal axis. The vertical axis intersects this crossing pointM of the horizontal axes. The central joint of the steering triangleand/or the fastening of at least one of the longitudinal control armsare mounted to the rigid vehicle axle according to the present inventionon the axle body with an offset from at least one of these axles.

“Offset” is defined here as any deviation from the central arrangementof the central joint. However, the offset may also assume the value zerowhen the central joint is fastened, e.g., centrally on the axle body.However, embodiments in which a differential is present on the axle andthe central joint is arranged laterally on this housing of thedifferential are possible as well. The central joint is now quasi in an“oblique position.”

According to the present invention, each molecular joint comprises acylindrical or spherical metallic inner part, whose fastening pinsproject from the housing on both sides.

A molecularly deformable elastomer body adhering to the two componentsis arranged between the housing and the inner part.

However, at least one of these two adhesive connections is able to slipthrough when a maximum allowable shear stress is exceeded, so thatdestruction of the elastomer body and consequently of the joint due toover stressing is effectively prevented from occurring. Adhesiveconnection is consequently. Defined according to the present inventionas an adhesive, but detachable connection.

However, slide bearings or pivoting slide bearings may also be usedbesides the molecular joints.

To make it possible to manufacture the entire vehicle axle with a smallnumber of individual parts and to correspondingly reduce themanufacturing and assembly efforts, it is advantageous to make themounting flange, which receives the central joint of the steeringtriangle, in one piece with the axle body.

The central joint of the steering triangle is regularly connecteddetachably to the mounting flange.

Corresponding to another embodiment of the present invention, it issuggested that the connection between the mounting flange and thecentral joint be designed as a screw connection, which has, e.g.,elongated holes at the fastening pins of the central joint to compensatetolerances.

The central joint and the guiding joints are preferably designed asmolecular joints. They may be fastened according to variousarrangements. For example, the inner part of the central joint may befixed axially parallel to the horizontal axis on the axle body, whichaxis also forms the central axis of the axle body, or at least one ofthe joints is arranged coaxially or axially in parallel to a verticalaxis on the vehicle. Furthermore, each joint may form an angle with thisvertical axis when projected into a common plane.

Corresponding to another embodiment of the present invention, at leastone of the joints comprises a metallic housing with a cylindrical innerjacket, a metallic inner part and an elastomer body arranged between thetwo. This compensates axial, radial and cardiac movements of the housingand of the inner part relative to one another by molecular deformation,and the elastomer body cooperating with the cylindrical inner jacket ofthe housing in the outward direction is adheringly arranged on the innerpart and is axially pretensioned between sheet metal rings and has acrowned jacket surface geometry centrally all around and a fitted jacketsurface geometry next to it on both sides all around in thepreassembled, axially stress-free state, wherein the external diameterof the sheet metal rings has an undersize compared with the internaldiameter of the inner jacket of the housing and a sliding surface on thecircumference of the elastomer body, which sliding surface is formedunder the axial tensioning and cooperates with the cylindrical innerjacket surface of the housing, allows a rotary movement of the innerpart in the housing, so that the inner part slips through underoverload.

Destruction and the associated premature failure of the joint andconsequently of the vehicle axle is thus prevented from occurring in asimple manner.

However, depending on the vehicle axle characteristic to be achieved andin light of a soft spring characteristic, it is also possible to use inan axle suspension according to the present invention molecular jointswhose housing is provided with a recess arranged inside the main loadzone. The radial direction is to be considered to be the principaldirection of loading in these molecular joints. The torsional loads aswell as the possible cardiac (angular) deflections are ratherunsubstantial and are hardly changed by a joint design according to thepresent invention. Such molecular joints have a ball piece as the innerpart. A thicker rubber layer is applied between the inner wall of thehousing and the ball surface due to a recess in the joint housing in theequatorial area of the ball piece. Since the rubber has dampingproperties, i.e., it is “soft,” such a joint has a softer springcharacteristic at the beginning of its radially acting load. However,the more the rubber is compressed, the more strongly will it be pressedagainst the housing wall. The characteristic of the joint thus becomesharder with increasing radial spring travel.

The elastomer body may be a one-layer or multilayer elastomer bodyaccording to the present invention and may optionally have insertsconsisting of metal or plastic.

According to the present invention, the steering triangle may be aone-part component made of plastic, fiber-reinforced plastic, magnesium,aluminum or steel, in whose mounts, which are prepared for this purpose,the molecular joints are inserted.

To better meet the mounting requirements, the control arms of thesteering triangle may also have different lengths. It is thus possible,e.g., to mount the central joint laterally next to the differential.

Moreover, advantages arise in terms of mounting from the fact that atleast one of the longitudinal control arms or of the control arms of thesteering triangle is bent at right angles in the area of the guidingjoints and/or of the central joint, so that the central longitudinalaxis of the control arm or of the control arms and the central axis ofthe guiding joint are offset in space in relation to one another. Thesteering triangle may also have arc-shaped control arms, as a result ofwhich steering triangle designs in which the angle formed by the controlarms is greater than 60° are possible.

According to the present invention, the steering triangle may alsocomprise two control arms connected to one another in the area of thecentral joint, where a two-part housing is used which receives thecentral joint in the form if a molecular joint. The housing parts arecharacterized by an assembly connection. Torsional movement of thehousing parts in relation to one another is possible.

The above-mentionhed features of the present invention and the featuresyet to be explained below can, of course, be used not only in thespecific combination indicated, but in other combinations or alone aswell without going beyond the scope of the present invention.

Some exemplary embodiments of the axle suspensions of rigid axlesaccording to the present invention will be explained in greater detailbelow with reference to the drawings.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying drawings and descriptive matter inwhich preferred embodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a top view of an axle suspension of a rigid axle according tothe present invention;

FIG. 2 is a top view of another axle suspension of a rigid axleaccording to the present invention;

FIG. 3 is a top view of another axle suspension of a rigid axleaccording to the present invention;

FIG. 4 is a side view showing an axle suspension of a rigid axleaccording to the present invention, with a steering triangle having aright-angle bend;

FIG. 5 is a side view showing another axle suspension of a rigid axleaccording to the present invention, with a steering triangle having aright-angle bend;

FIG. 6 is a side view showing another axle suspension of a rigid axleaccording to the present invention, with a steering triangle having aright-angle bend;

FIG. 7 is a top view showing another embodiment of a rigid vehicle axleaccording to the present invention with the steering triangle fastenedunder the axle body;

FIG. 8 is a top view showing another embodiment of a rigid vehicle axleaccording to the present invention with the steering triangle fastenedabove the axle body;

FIG. 9 is a partial sectional view showing a section through anembodiment of a molecular.joint as it is used in an axle suspensionaccording to the present invention;

FIG. 10 is a sectional view showing a section through another embodimentof a molecular joint as it is used in an axle suspension according tothe present invention;

FIG. 11A is a sectional view showing a section through anotherembodiment of a molecular joint as it is used in an axle suspensionaccording to the present invention;

FIG. 11B is a sectional view showing a section through the embodiment ofthe molecular joint of FIG. 11A as it is used in an axle suspensionaccording to the present invention and showing the crowned jacketsurface geometry;

FIG. 12 is a three-dimensional view of an axle suspension according tothe present invention;: and

FIG. 13 is a side view showing an axle suspension of a rigid axleaccording to the present invention with a steering triangle having aright-angle bend as well as a longitudinal control arm having, aright-angle bend.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in particular, FIGS. 1 through 3 show axlesuspensions of rigid axles according to the present invention,which havespecific peculiarities, even though their basic design is similar. Thefigures show axle suspensions of rigid axles on the axle body 1 of whicha steering triangle 2 as well as two longitudinal control arms 3,4,which are located at spaced locations from the steering triangle andhave different vertical positions, and an additional stabilizing device5 are arranged. The steering triangle 2 has two control arms 2.1 and2.2, which form an angle a with one another and are fastened to acentral joint 2.3, on the one hand, and are connected to the vehiclebody via a guiding joint 2.4 and 2.5 each, on the other hand. Thelongitudinal control arms 3, 4 have a molecular joint 3.1, 3.2 and 4.1,4.2 each on both sides. Each molecular joint comprises a metallic innerpart 6, whose fastening pins 7, 8 project from the housing 9 on bothsides. A molecularly deformable elastomer body, which adheres to bothcomponents, is located between the housing 9 and the inner part 6, andat least one of these two adhesive connections slips through when amaximum allowable shear stress is exceeded. The central joint 2.3 of thesteering triangle 2 is mounted on the axle body with an offset inrelation to at least one of the axes 11 through 13. In FIG. 1, thecentral joint 2.3 is arranged on the axle body I offset axially inparallel to the first horizontal axis 12 and in the direction of thisaxis 12. The offset in this case is the distance between the centraljoint 2.3 and the vertical axis 11 and is designated by “A” in thefigure. The geometric center “M” may be located to the left or right ofthe central joint, which is indicated by “±A.” Moreover, the controlarms 2.1, 2.2 of the steering triangle have different lengths.

In the embodiment according to FIG. 2, the central joint is mountedtruly axially, i.e., the offset equals zero here. The peculiarity ofthis vehicle axle is the vertically arranged molecular joints 2.4 and2.5 present at the ends of the control arms 2.1, 2.2.

FIG. 3 shows another advantageous embodiment of the present invention.The fastening pins 7 and 8 of the central joint 2.3 now have elongatedholes 7.1 and 8.1, which make it possible to compensate tolerances andto simplify the mounting of the steering triangle on the axle. Accordingto the present invention, the mounting of the central joint is notlimited to the connection to the vehicle axle shown in FIG. 3. Thefastening pins of the central joint and of the guiding joints may ratherbe arranged not only axially in parallel to the horizontal axis 12, but,e.g., also vertically to this or in any desired angular position.

FIGS. 4 through 6 schematically show various possible axle embodimentsaccording to the present invention. In the embodiment according to FIG.4, the longitudinal control arms 3, 4 have an offset “B” from thevertical axis 11. Consequently, they are arranged offset to the frontwhen viewed in the direction of travel. The steering triangle 2 is bentat a right angle on both sides, so that the central axis 16 of theguiding joint has a distance “D” (offset) from the central longitudinalaxis 15 of the steering triangle. In the embodiment according to FIG.13, the longitudinal control arms 3,4 have been offset a distance “B”from the vertical axis 11 and also are bent at a right angle so thatthere is an offset “F” from a central axis of the joint “3.2 or 4.2” andthe central axis of the longitudinal control arm 25.

Moreover, the steering triangle 2 is mounted on the axle body 1 with anoffset “C” from the vertical axis 11 in FIG. 5.

In the embodiment according to FIG. 6, the steering triangle is bent ata right angle on one side only and the design of this axle suspension isotherwise identical to that shown in FIG.5

FIG. 7 shows the design of a vehicle axle according to the presentinvention for low-platform vehicles. The steering triangle 2 is mountedunder the vehicle axle, while the longitudinal control arms 3, 4 arefixed above same. This design makes it possible to save a considerableamount of installation space. These vehicles can be lower thanconventional ones.

In FIG. 8, the stabilizing device 5 is integrated by being mounted inthe longitudinal control arms 3, 4. A one-part design of thelongitudinal control arms and of the stabilizing device may, of course,be used as well. The vehicle axle becomes very narrow due to such adesign, because all stabilizing components can be arranged on one side,while the effort needed for mounting is reduced at the same time and thenumber of components can be reduced on the whole.

FIGS. 9 through 11 once again show embodiments of various molecularjoints as they can be used in each of the described joints of an axleaccording to the present invention.

The molecular joint in FIG. 9 has a housing 9 with a recess 9.2 arrangedinside the main load zone. The radial direction is to be considered tobe the main direction of load. The inner part 6 is a ball piece. Athicker rubber layer is applied between the inner wall 9.2 of thehousing and the ball surface due to the recess 9.2 in the joint housing9, immediately in the equatorial area. Since the rubber possessesdamping properties, i.e., it is “soft,” such a joint has a softer springcharacteristic at the beginning of its radially acting load. However,the more the rubber is compressed, the more strongly will it be pressedagainst the housing wall. The joint characteristic thus becomes harderwith increasing radial spring travel.

The molecular joint in FIG. 10 is a joint consisting of a plurality ofelastomer layers 10.1 and 10.2. Inserts 20 consisting of metal orplastic, which affect the mounting characteristic, are introducedbetween the elastomer layers. These inserts 20 may in turn haverecesses. The inner part 6 has a cylindrical design in this joint.

The guiding joint shown in FIG. 11 comprises a metallic housing 9 with acylindrical inner jacket 9.1, a metallic, spherical inner part 6 and anelastomer body 10 arranged between the two, which compensates axial,radial and cardiac movements of the housing and of the inner partrelative to one another by molecular deformation.

The elastomer body 10 cooperating with the cylindrical inner jacket 9.1of the housing radially in the outward direction is arranged adheringlyon the inner part and is also axially pretensioned between sheet metalrings 18, 19. It has a crowned jacket surface geometry centrally allaround and a fitted jacket surface geometry next to it on both sides allaround in the preassembled, axially stress-free state, wherein theexternal diameter of the sheet metal rings has an undersize comparedwith the internal diameter of the inner jacket 9.1 of the housing. Asliding surface on the circumference of the elastomer body, whichsliding surface is formed under the axial tensioning and cooperates withthe cylindrical inner jacket surface of the housing, allows a rotarymovement of the inner part in the housing, so that the inner part slipsthrough under overload.

FIG. 12 shows a three-dimensional representation of an axle suspensionof rigid axles according to the present invention. The axes ofcoordinates formed by the axes 11, 12 and 13 are shown in the figure.The steering triangle 2 is mounted, e.g., truly centrally on themounting flange 14. The offset of the steering triangle is present hereonly relative to the horizontal axes 12 and 13, but its value is zerorelative to axis 11. The intersection of the axes 11, 12 and 13 isdesignated by “M” in FIG. 12.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:
 1. An axle suspension of a rigid axle, on an axlebody, the axle suspension comprising: a steering triangle with a centraljoint and two control arms, said steering triangle control arms formingan angle with one another and being each respectively fastened to saidcentral joint at one end and connected to a vehicle body via a guidingjoint at another end; two longitudinal control arms located at spacedlocations from the steering triangle and having a different verticalposition from the steering triangle, each of said two longitudinalcontrol arms being connected to a respective longitudinal control armjoint; a stabilizing device, geometric axes of coordinates being definedfor the axle suspension including a first horizontal axis extending in atransverse direction of the vehicle and forming a central axis of theaxle body, a second horizontal axis extending in the center of thevehicle and in a longitudinal direction of the vehicle and intersectingsaid first horizontal axis at light angles at an intersection, and avertical axis intersecting said intersection, at least one of saidcentral joint of said steering triangle and the respective longitudinalcontrol arm joint of at least one of said longitudinal control armsbeing mounted on said axle body with an offset in relation to at leastone of said first horizontal axis, said second horizontal axis and saidvertical axis, wherein at least one of said longitudinal control arms isbent at a right angle in the vicinity of the respective longitudinalcontrol arm joint or at least one of said control arms of said steeringtriangle is bent at a right angle in the vicinity of the central joint,so that a longitudinal central axis of the control arm and a centralaxis of the central joint are offset from one another in space or one ofthe longitudinal control arms and the respective longitudinal controlarm joint are offset from one another in space.
 2. An axle suspension ofrigid axles in accordance with claim 1, wherein each of said centraljoint of said steering triangle and the respective longitudinal controlarm joints is a molecular joint, said molecular joint comprising ahousing, a metallic inner part with fastening pins projecting from saidhousing on both sides and a molecularly deformable elastomer bodyadhering to said metallic inner part and said housing, said molecularlydeformable elastomer body being arranged between said housing and saidmetallic inner part by two adhesive connections, wherein at least one ofsaid two adhesive connections slips through when a maximum allowableshear stress is exceeded.
 3. An axle suspension of rigid axles inaccordance with claim 1, wherein at least one of said central joint andsaid respective longitudinal control arm joints is a slide bearing or apivoting slide bearing.
 4. An axle suspension of rigid axles inaccordance with claim 1, further comprising: a mounting flange made inone piece with said axle body.
 5. An axle suspension of rigid axles inaccordance with claim 4, wherein said central joint of said steeringtriangle is detachably connected to said mounting flange of the axlebody.
 6. An axle suspension of rigid axles in accordance with claims 5,wherein the connection between said mounting flange and said centraljoint is a screw connection.
 7. An axle suspension of rigid axles inaccordance with claim 6, wherein said central joint has fastening pinswith elongated holes to compensate tolerances.
 8. An axle suspension ofrigid axles in accordance with claim 1, wherein said central joint is amolecular joint which comprises a metallic inner part and a molecularlydeformable elastomer body, said inner part being fixed on the axle bodyaxially in parallel to said first horizontal axis.
 9. An axle suspensionof rigid axles in accordance with claim 2, wherein at least one of themolecular joints is arranged on the vehicle coaxially or axially inparallel to said vertical axis or, projected into a common plane, itforms an angle with said vertical axis.
 10. An axle suspension of rigidaxles in accordance with claim 2, wherein at least one of the molecularjoints comprises an cylindrical inner jacket of said housing, saidelastomer body cooperates with said cylindrical inner jacket radially inthe outward direction, said elastomer body being arranged adheringly onthe inner jacket and is axially pretensioned between sheet metal ringsand has a crowned jacket surface geometry centrally all around and afitted jacket surface geometry next to it on both sides all around inthe preassembled, axially stress-free state, wherein the externaldiameter of said sheet metal rings is undersized compared with theinternal diameter of said inner jacket of the housing and a slidingsurface on the circumference of the elastomer body, which slidingsurface is formed under the axial tensioning and cooperates with thecylindrical inner jacket surface of the housing, allows a rotarymovement of the inner part in the housing, so that the inner part slipsthrough under overload.
 11. An axle suspension of rigid axles inaccordance with claim 2, wherein said housing of at least one of saidmolecular joints is provided with an inner recess arranged within a mainload zone and has a ball piece as said inner part.
 12. An axlesuspension of rigid axles in accordance with claim 2, wherein said jointof said steering triangle is a molecular joint, said molecular jointcomprising a housing, a metallic inner part with fastening pinsprojecting from said housing on both sides and a molecularly deformableelastomer body adhering to said metallic inner part and said housing,said molecularly deformable elastomer body being arranged between saidhousing and said metallic inner part, said elastomer body being amultilayer elastomer body arranged between said housing and said innerpart.
 13. An axle suspension of rigid axles in accordance with claim 2,wherein at least one of said molecular joints has a cylindrical innerpart.
 14. An axle suspension of rigid axles in accordance with claims 1,wherein said steering triangle is a one-part component formed ofplastic, plastic composite, magnesium, aluminum or steel, having mounts,prepared to receive molecular joints as inserts.
 15. An axle suspensionof rigid axles in accordance with claim 1, wherein said control arms ofsaid steering triangle have different lengths.
 16. An axle suspension ofrigid axles in accordance with claim 1, wherein an angle (α) betweensaid control arms of said steering triangle is greater than 60°.
 17. Anaxle suspension of rigid axles in accordance with claim 1, wherein saidsteering triangle is fastened under the axle body.
 18. An axlesuspension of rigid axles in accordance with claim 8, wherein saidsteering triangle comprises two control arms connected to one another inthe area of said central joint.
 19. An axle suspension of a rigid axle,on the axle body, the axle suspension comprising: a steering trianglewith a central joint and two control arms, said steering trianglecontrol arms forming an angle with one another and being eachrespectively fastened to said central joint at one end and connected toa vehicle body via a guiding joint at another end; two longitudinalcontrol arms located at spaced locations from the steering triangle andhaving different vertical positions; a stabilizing device, geometricaxes of coordinates being defined for the axle suspension including afirst horizontal axis extending in a transverse direction of the vehicleand forming a central axis of the axle body, a second horizontal axisextending in the center of the vehicle and in a longitudinal directionof the vehicle and intersecting said first horizontal axis at rightangles at an intersection, and a vertical axis intersecting saidintersection, at least one of said central joint of said steeringtriangle and a fastening of at least one of the said longitudinalcontrol arms being mounted on said axle body with an offset in relationto at least one of said first horizontal axis, said second horizontalaxis and said vertical axis, wherein said control arms of said steeringtriangle arc bent at a right angle in the vicinity of the central joint,so that a longitudinal central axis of the control arms and a centralaxis of the central joint are offset from one another in space.